Rotary gas/liquid separator

ABSTRACT

A rotary gas/liquid separator includes a housing having a free running rotor mounted to rotate about a vertical axis in the housing. The rotor has an inverted conical inside surface, and a plurality of turbine blades adjacent an upper end of the conical inside surface. A gas/liquid inlet mixture is forced under pressure through stator vanes for directing flow of the inlet mixture tangentially into the turbine blades for rotating the rotor. The turbine blades divert the inlet mixture radially outwardly and then axially downwardly toward the conical inside surface of the rotor, and centrifugal force exerted on the inlet mixture by the rotating turbine blades separates liquid from the gas in the inlet mixture. The separated liquid flows downwardly in a thin film along the inside surface of the rotor and drips from a free lip at the bottom of the rotor for collection. A plurality of fan blades on the rotor discharge separated gas from a first chamber below the rotor to a second chamber above the rotor. A substantial pressure drop and corresponding adiabatic cooling of the gas results from passage of the gas through the turbine blades, and the fan blades increase the pressure and temperature of the gas in the second chamber relative to gas pressure and temperature in the first chamber.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 939,479, filed Sept. 5,1978, now abandoned.

BACKGROUND

This invention relates to a gas/liquid separator particularly useful forseparating crude oil and natural gas from recovered oil and gas wells.

In the past, various types of gas/liquid separators have been used inoil fields for separating valuable crude oil from natural gas in wellfluids pumped from oil or gas wells.

The present invention provides a gas/liquid separator having a freerunning rotor. A gas/liquid inlet mixture, such as well fluid, can beadmitted under pressure into the rotor for impinging on the rotor torotate it about its axis. Impingement and centrifugal force exerted bythe rotor on the inlet fluid can separate liquid from gas in the fluid.

U.S. Pat. No. 3,879,949 discloses a gas/liquid separator having a freelyrotating ring for separating liquid from gas. The separated liquid isextracted from the periphery of the ring by a pitot tube. However, wellfluid from oil or gas wells can contain iron particles, sand and otherdebris from an oil well, which could unduly erode a pitot tube.

There is a need to provide a gas/liquid separator which can effectivelyremove as much liquid as possible from gas in a gas/liquid inletmixture. There is also a need to provide a separator which caneffectively separate liquid, and particulate solids, from gas in wellfluids without the need for using a pitot tube or similar pickup.

SUMMARY OF THE INVENTION

The present invention, according to one embodiment, provides agas/liquid separator comprising a housing, and a free running rotormounted for rotation about a vertical axis in the housing. The rotor hasa downwardly diverging inside surface and a plurality of turbine bladesadjacent an upper end of the inside surface. A gas/liquid inlet mixtureis directed into the turbine blades for rotating the rotor about itsaxis and for exerting centrifugal force on the inlet mixture forseparating liquid from the gas. A plurality of fan blades on the rotorare in gas communication with a chamber below the rotor for receivingseparated gas. Rotation of the fan blades discharge gas from the chamberat a gas pressure higher than the pressure in the chamber.

In one embodiment of the invention, the inlet mixture is forced throughone or more nozzles provided by a plurality of stator vanes fordirecting the inlet mixture into the turbine blades. The turbine bladesact as a diffuser to produce a pressure drop and corresponding adiabaticcooling of separated gas evolved in the chamber below the rotor. The fanblades on the rotor withdraw separated gas from the chamber and act as acompressor for increasing the pressure and temperature of the separatedgas.

DRAWINGS

These and other aspects of the invention will be more fully understoodby referring to the following detailed description and the accompanyingdrawings, in which:

FIG. 1 is a fragmentary vertical cross-sectional view showing agas/liquid separator constructed according to principles of thisinvention;

FIG. 2 is a transverse cross-sectional view taken on line 2--2 of FIG.1; and

FIG. 3 is an enlarged fragmentary vertical cross-sectional view showingthe apparatus within the circle 3 of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates a vertical cross-section of an embodiment of agas/liquid separator constructed according to principles of thisinvention. The gas/liquid separator includes a cylindrical outer housing10 having a hollow interior. A rotor 12 is mounted for rotation about avertical axis in the interior of the housing. The rotor surrounds anelongated vertical shaft 14 inside the housing. The rotor is rigidlyaffixed to the shaft so that the rotor and the shaft can rotate togetherabout a vertical axis through the shaft.

The rotor includes a downwardly opening annular shell 15 spaced radiallyoutwardly from the shaft. The shell is shaped generally as an invertedcone in vertical cross-section, as illustrated in FIG. 1. An outer wallof the shell is formed by an annular downwardly diverging outer rim 16.The rim has an inverted conical inside surface 18 which divergesdownwardly and outwardly from an upper portion of the shell to acircular free lip 20 at the bottom of the rotor. The lip at the bottomof the rotor is termed a free lip in the sense that a film of liquidflowing downwardly under gravity along the conical inside surface 18 ofthe rim can drip freely under gravity from the bottom lip into a lowerreservoir for collection.

An upper inside portion of the shell 15 is formed by an annulargenerally conical inner wall 22 which converges diagonally downwardlyand inwardly toward the axis of the shaft 14 from an upper portion ofthe rim. A lower portion of the inner wall 22 is integral with an upperportion of a vertically extending ring 24 which surrounds a lowerportion of the shaft. The vertical ring 24 forms a lower inside wall ofthe shell.

The top of the outer rim 16 is shaped generally as a hook forming aninwardly extending annular flange 26. An inside surface of the annularflange is spaced above and radially outwardly from an annular lip 28 atthe top of the shell inner wall 22. This forms an annularradial-to-axial gas flow passage 30 between the inside surface of theflange and an outer portion of the lip. The radial-to-axial gas flowpassage has a radially outwardly extending inner portion with an inlet32 spaced relatively closer to the axis of the shaft 14 and a generallyaxially extending outer portion with an outlet 34 spaced relativelyfarther from the axis of the shaft. The radial-to-axial gas flow passageextends radially outwardly from the shaft and then curves to extenddownwardly and generally axially adjacent an upper end of the invertedconical inside surface 18 of the shell.

A plurality of circumferentially spaced apart turbine blades 36 extendradially across the gas flow passage 30. The turbine blades are straightand extend radially outwardly on respective radii with respect to theaxis of the shaft 14. That is, the radial extent of each turbine bladeis on a radial line passing through the axis of the shaft 14. Eachturbine blade is essentially continuous from the inlet to the outlet ofthe radial-to-axis gas flow passage 30. Thus, each turbine blade has aninner portion which extends radially outwardly from the shaft and thencurves downwardly to form a generally axially extending outer portionadjacent the upper end of the inverted conical inside surface 18.

The inside portion of the rotor includes a mounting ring 38 rigidlyaffixed to a lower portion of the shaft. The outside of the mountingring is spaced apart radially from the inside of the vertical ring 24which forms the lower inside wall of the shell. This forms an annulargas flow passage 40 between the inside of the shell inner wall and theoutside of the mounting ring. The rotor includes a plurality ofcircumferentially spaced apart fan blades 42 extending radially throughthe annular gas flow passage 40. Inside portions of the fan blades areintegral with the outside of the mounting ring, and outer portions ofthe fan blades are integral with the inside of the vertical ring 24.Thus, the fan blades rotate with corresponding rotation of the rotor andthe shaft, and the fan blades form a compressor stage at the lowerinside portion of the rotor. The fan blades extend radially with respectto the axis of the shaft, i.e., the radial extent of the fan blades ison a line passing through the axis of the shaft. The mounting ring 38 issecured to a flange 44 at the lower portion of the shaft. The fan bladesextend vertically upwardly continuously from a lower edge of themounting ring to an upper edge of the mounting ring. The upper edges ofthe fan blades are essentially level with the upper edge of the lowervertical ring inside the shell.

A lower O-ring seal 46 seals a lower portion of the mounting ring to theshaft immediately above the flange 44. An upper portion of the mountingring has an annular inside recess adjacent the shaft 14, and a sealfacing ring 48 in the recess maintains an O-ring seal 50 against therecessed portion of the mounting ring.

The rotor is mounted for rotation below a fixed bearing housing 52 whichcontains a means for supplying bearing lubricant to bearings supportingthe rotor shaft for rotation inside the bearing housing. The bearinghousing also contains gas flow passages for diverting the flow ofseparated gas toward an outlet of the separator and for recovering thetangential velocity energy of the gas leaving the fan blades 42. Thebearing housing is rigidly affixed to the base of a cylindricalreservoir 56 for containing a supply or bearing lubricant. Thereservoir, shown primarily in vertical cross-section in FIG. 1, is fixedwithin the housing 10 above the portion of the separator shown inFIG. 1. The bearing housing 52 includes a cylindrical inner wallstructure 58 having a flanged top portion 60 rigidly secured and sealedto the base of the reservoir 56. The inner wall structure 58 of thebearing housing extends downwardly from the reservoir and surrounds theshaft 14, terminating immediately above the top edge of the rotormounting ring 38.

The inside of the inner wall structure 58 is spaced radially outwardlyfrom the shaft 14, and the inner wall structure is supported on theoutside of an elongated tubular shaft bearing 62 supported on the shaft14. The tubular shaft bearing 62 has a fixed inwardly projecting bearingring which carries an upper rotating bearing 64 which rotates with therotor shaft 14. Similarly, a lower portion of the bearing tube has afixed inwardly projecting lower bearing ring which carries a lowerrotating bearing 66 which rotates with the shaft.

The inner wall structure 58 of the bearing housing 52 also includes aninwardly projecting bottom lip 68 which carries an annular seal ring 70having a small annular clearance around the shaft immediately above theconnection between the shaft and the rotor. The seal ring 70 maintainsan O-ring seal 72 in contact with an inside annular edge of the bottomlip 68.

The bearing housing 52 includes preferably four circumferentially spacedapart elongated gas flow discharge passages 74 extending upwardly awayfrom the fan blades 42 essentially parallel to the rotor shaft. The fourgas flow discharge passages are curved when viewed from above. Thedischarge passages are each curved with the same radius centered on theaxis of the shaft. The discharge passages are equal in length andequidistantly spaced apart within the bearing housing. The dischargepassages are separated by four circumferentially spaced apart elongatedvertically extending support ribs 76 which are equidistantly spacedapart within the bearing housing. The support ribs function asstationary blades which act as a diffuser helping to recover thevelocity energy of the gas leaving the fan blades 42. Each dischargepassage 74 has an inlet immediately above the top of the fan blades 42and an outlet 78 between the inside wall structure 58 and an outer wallstructure 80 of the bearing housing. The outer wall structure surroundsthe inner wall structure 58 of the bearing housing, and the support ribs76 support the outer wall structure around the inner wall structure.

An annular inlet housing 82 is affixed, in part, to the outer wallstructure 80 of the bearing housing 52. An outer portion of the inlethousing includes a radially inwardly extending inlet port 84 forreceiving flow of a gas/liquid mixture to be separated by the separator.The inlet port opens into an inner cavity 86 which is part of an annulargas flow inlet passage 88 formed between the inside of the inlet housingand the outside of the outer wall structure 80. A radial lower portion90 of the annular inlet passage extends radially outwardly toward theinlet end of the radial-to-axial gas flow passage 30 and turbine blades36 of the rotor 12. The radial lower portion 90 of the inlet passageincludes a plurality of circumferentially spaced apart curved statorvanes 92. The stator vanes extend generally radially outwardly from theaxis of the shaft 14, and when viewed in plan view, as in FIG. 2, thestator vanes are curved to direct flow of a gas/liquid inlet mixturegenerally tangentially into the turbine blades of the rotor. This causesthe rotor to rotate about the axis of the shaft, and when viewed as inFIG. 2, rotation of the rotor is in a clockwise direction. Thus, thestator vanes are curved in the direction of rotation of the rotor as thestator vanes extend from relatively nearer the rotor axis to relativelyfarther from the rotor axis. The radial portion of the inlet passage andthe stator vanes are spaced relatively closer to the axis of the shaftthan the turbine blades on the rotor.

The radial portion 90 of the inlet passage is substantially reduced intransverse cross-section when compared with the inlet portion 84. Thestator vanes 92 cooperate with the reduced area of the radial inletpassage to form circumferentially spaced apart jet nozzles for forcing afluid inlet mixture radially outwardly under pressure into the turbineblades of the rotor. The jet nozzles provided by the stator vanescooperate with the turbine blades of the rotor to form an impulseturbine, and a fluid inlet mixture directed through the nozzles againstthe turbine blades rotate the rotor and the shaft about the verticalaxis of the shaft in response to impingement of the fluid inlet mixtureon the turbine blades. The rotor is considered a free running rotor inthe sense that no other means of motive power, other than theimpingement force exerted on the rotor by the inlet fluid is required torotate the rotor.

A flanged upper portion of the inlet housing is rigidly affixed andsealed to the top of the outer wall structure 80 of the bearing housing.An O-ring seal 94 seals an annular bottom lip 96 of the inlet housing toa flanged lower portion 98 of the bearing housing.

The inlet housing 82 has a peripheral flange 99 which rests on top of amount ring 100 which is rigidly affixed inside the outer housing 10. Theflange 99 is rigidly affixed to the top of the mount ring for securingthe gas/liquid separator inside the housing. The rotor is thus able torotate about the vertical axis of the shaft 14 within the confines ofthe mount ring 100. A rubber ring 102 is rigidly affixed to the insideof the mount ring and surrounds a lower edge of the rotor. A collectionbasin (not shown) is located within the housing below the bottom of therotor.

Referring to FIG. 1, the reservoir 56 includes a flexible diaphragm 104enclosing the bearing lubricant oil 57 contained in the reservoir. Amovable piston 106 in an upper inside portion of the reservoir appliespositive downward pressure on the diaphragm 104 for applying a slightpositive pressure on the bearing lubricant so that the bearings do notrun dry. A horizontally extending baffle plate or shroud 108 extendsradially outwardly from an upper portion of the shaft bearing 62 intothe lower portion of the reservoir.

A stationary thrust bearing 110 supports an upper portion of the fixedbearing housing 52 around the upper portion of the rotatable shaft 14. Arotatable thrust washer 114 is secured to the shaft above the bearingtube 62. The thrust washer is mounted against the rotatable upperportion of the upper bearing 64 in the bearing tube. The interior of thethrust bearing contains an annular lubricant circulating passage 116. Aplurality of radial upper grooves 118 extend radially outwardly throughan upper portion of the thrust bearing, and a plurality of similarradial lower grooves 120 extend radially outwardly through a lowerportion of the thrust bearing. The upper radial grooves 118 providefluid communication between the annular passage 116 in the thrustbearing and the lower inside portion of the reservoir. The lower groovesprovide fluid communication between a plurality of vertical grooves 122in the upper bearing 64 of the bearing tube 62 and the annular passage116 in the thrust bearing. The annular passage in the thrust bearing isin fluid communication with an outlet port 124 for bearing lubricantpassing outwardly from the thrust bearing into the lower portion of thereservoir. An inlet port 126 in an upper portion of the bearing housingprovides an inlet for bearing lubricant below the baffle plate 108. Theinlet port 126 provides an inlet to the top of a vertically extendingannular outer bearing lubricant passage 128 extending through thebearing housing to an annular passage 130 at the bottom of the bearingtube 62. The annular passage 130 opens into the bottom of a verticallyextending inner bearing lubricant circulating passage 132 whichsurrounds the rotor shaft 14 inside the bearing tube 62. The top of theinner lubricant passage 132 communicates with the bottom of thecircumferentially spaced apart vertical bearing lubricant passages 122which, in turn, provide for the passage of bearing lubricant through theradial lower grooves 120 in the thrust bearing 110.

In using the gas/liquid separator, a fluid inlet mixture of liquid andgas enters the inlet port 84 of the separator. The inlet mixture cancontain a mixture of oil, water and natural gas introduced at anelevated inlet pressure of a few hundred psi. The inlet mixture is thenforced radially outwardly through the nozzles provided by the statorvanes 92 for forcing the inlet fluid generally tangentially into theturbine blades. The impingement on the turbine blades provides motivepower for rotating the rotor and the shaft about the vertical axis ofthe shaft. The inlet mixture passes radially outwardly through theturbine blades and is then diverted downwardly and outwardly by theturbine blades toward the upper end of the conical inside surface 18 ofthe rotor. The impingement force and the high centrifugal force exertedon the inlet mixture by the rotating turbine blades provide means forseparating liquid from the gas in the inlet mixture.

The separated liquid flows downwardly under gravity in a thin film alongthe inverted conical inside surface 18 of the rotor. The thin film ofliquid, together with its relatively long residence time in the rotor,are effective in allowing dissolved gas to be evolved inside the rotorshell. The separated liquid drips off the bottom lip of the rotor intothe basin below the rotor for collection. The separated liquid also canbe spun outwardly against the rubber ring 102 surrounding the lower edgeof the rotor. The separated liquid can drip from the rubber ring to thecollection basin. The free lip 20 at the base of the inverted conicalrotor allows entrained solids to fall into the collection basin.

The inlet mixture passing through the turbine blades is diffused by theturbine blades into the inside of the rotor, and the elevated pressureof the inlet mixture is reduced substantially in the turbine blades inconverting this energy to motive power for running the rotor.Substantially all of the gas pressure drop occurs across the turbineblades. There is essentially no pressure drop inside the rotor shellbelow the turbine blades. Gas which has been separated from the liquidpasses into a first chamber 134 below the rotor. The pressure drop ofgas separated by the turbine is accompanied by adiabatic cooling of thegas in the first chamber below the rotor. The lower temperature of theseparated gas provides for improved condensation of any liquid which hasnot been separated from the gas by passage through the turbine, and anycondensed liquid can fall under gravity into the collection basin belowthe rotor.

The gas separated from the liquid is withdrawn from the first chamber134 from relatively near the shaft axis of rotation by the rotating fanblades 42 near the bottom inside of the rotor. The rotating fan bladesdraw the separated gas upwardly into the annular gas flow passage 40 inthe bottom in the rotor. The gas drawn into the fan blades continues tobe drawn upwardly through the discharge passages 74 between the fixedsupport ribs 76, and this gas passes outwardly into a second chamber 136above the rotor and is eventually discharged through an outlet (notshown) from the separator housing. The rotating fan blades act as acompressor to raise the pressure of the separated gas so that gaspressure in the compressor stage, as well as in the second chamber 136,is greater than the gas pressure in the first chamber below the rotor.The temperature of the separated gas also is increased by its passagethrough the compressor stage. The increased pressure of gas drawnthrough the compressor aids in circulating separated gas away from therotor and toward the outlet above the rotor. The increase in pressureand temperature of the compressed outlet gas also aids in drying theoutlet gas to further remove any entrained liquid from the outlet gas.

A clearance 140 (see FIG. 1) is present between an annular edge of therotor below the inside edges of the turbine blades 36 and an annularedge of the inlet housing 82 below the outside edges of the stator vanes92. The head produced by the rotating fan blades 42 is as great orgreater than the pressure in the inlet stream at the clearance 140. Thehead produced by the compressor stage thus inhibits any tendency ofliquid in the inlet stream to pass through the clearance 140 and reachthe discharge passage 74.

Since the free running rotor operates continuously for a substantialperiod of time, the bearing lubricant is continuously circulated fromthe reservoir to the bearings on the rotor shaft. Continuous rotation ofthe rotor produces a centrifugal pumping action of continuouslycirculating bearing lubricant from the reservoir to the bearings. Theradial grooves in the thrust bearing rotate with the thrust bearing tocause the centrifugal pumping action which draws bearing lubricant intothe bearing housing and discharges bearing lubricant from the radialgrooves. Bearing lubricant is drawn below the baffle plate 108 into theinlet port 120 and then flows downwardly through the annular outerlubricant passage, into the annular passage 130 at the base of thebearing tube 62, and then upwardly to the lower bearing 66, into theinner lubricant passage 132, then to the upper bearing 64, and outthrough the lower grooves 120. Bearing lubricant also is drawn throughthe annular passage 116 in the thrust bearing and out through the upperradial grooves 118.

The gas/liquid separator can be adjusted for various flow rate levels byplacing a removable stationary blankout strip (not shown) on the staticportion of the separator adjacent the outlet of the jet nozzles (statorvanes 92). The blankout strip can be circularly curved and can extendfor a predetermined distance to block off a desired number of jetnozzles.

Thus, the liquid/gas separator provides a free running rotor havingturbine blades adjacent stator blades which cooperate to form an impulseturbine for supplying motive power to the free running rotor. Aliquid/gas mixture passing through the turbine blades is separated, andliquid automatically can travel under gravity into a lower reservoir forcollection. A substantial pressure drop occurs across the turbine, withcorresponding adiabatic cooling of the separated gas for condensingliquid remaining in the separated gas. The compressor stage drawsseparated gas away from the rotor and increases the pressure of thedischarged gas stream. The compressed gas also can be dried in thecompressor stage and the compressor stage produces a head which opposesany tendency of liquid from the inlet stream to leak into the gasdischarge passages on the outlet side of the compressor stage. The freerunning rotor automatically produces a continuous oil pumping system forsupplying bearing lubricant to the bearings of the rotor.

What is claimed is:
 1. A gas/liquid separator comprising:a housing; afree-running rotor mounted for rotation about a vertical axis in thehousing, the rotor having a downwardly extending inside surface andbeing open at its lower end; means for directing a gas/liquid mixtureinto the inside of the rotor for rotating the rotor; a chamber in thehousing below the rotor for receiving separated gas and liquid; and aplurality of fan blades on the rotor in gas communication with thechamber for discharging gas from the chamber at a pressure higher thanthe pressure in the chamber.
 2. A gas/liquid separator according toclaim 1 including a free lip at the bottom of the inside surface fordischarging liquid into the chamber.
 3. A gas/liquid separator accordingto claim 1 comprising a plurality of turbine blades on the rotoradjacent an upper end of the inside surface, and wherein the means fordirecting a mixture into the rotor comprises at least one nozzle fordirecting a gas/liquid mixture under pressure against the turbineblades.
 4. A gas/liquid separator according to claim 3 in which such anozzle comprises means for directing the gas/liquid mixture outwardlyfrom a nozzle inlet relatively nearer the rotor axis toward a nozzleoutlet relatively farther from the rotor axis.
 5. A gas/liquid separatoraccording to claim 4 in which the turbine blades are spaced farther fromthe rotor axis than the outlet of the nozzle.
 6. A gas/liquid separatoraccording to claim 1 including a second chamber above the rotor, and inwhich the fan blades discharge separated gas upwardly from the chamberbelow the rotor to the second chamber at a gas pressure higher than thepressure in the chamber below the rotor.
 7. A gas/liquid separatoraccording to claim 1 wherein the rotor includes a shaft; bearing meanssupporting the rotor on the shaft; a reservoir for containing a bearinglubricant; and means for diverting bearing lubricant from the reservoirto the bearing means for lubricating the bearing means.
 8. A gas/liquidseparator according to claim 7 including means for applying a positivepressure to bearing lubricant in the reservoir.
 9. A gas/liquidseparator according to claim 8 including a bearing lubricant passage forcirculating bearing lubricant to the bearing means; and centrifugal pumpmeans communicating with the bearing lubricant passage and rotating withrotation of the shaft for causing bearing lubricant to flow through thebearing lubricant passage.
 10. A gas/liquid separator according to claim1 wherein the inside surface of the rotor diverges downwardly.
 11. Agas/liquid separator according to claim 1 further comprising a pluralityof turbine blades on the rotor adjacent an upper end of the insidesurface.
 12. A gas/liquid separator comprising:a housing having an inletfor a gas/liquid mixture to be separated; a rotor mounted for rotationabout a vertical axis in the housing, the rotor having an insideperipheral surface; a plurality of turbine blades on the rotor adjacentan upper end of the inside peripheral surface of the rotor; meansbetween the inlet and the turbine blades for directing a gas/liquidmixture into the turbine blades for rotating the rotor for exertingcentrifugal force on the gas/liquid mixture to separate the liquid fromthe gas such that the separated liquid flows downwardly under gravityalong the inside peripheral surface of the rotor; and compressor meanson the rotor for discharging separated gas from a portion of the rotorbelow the turbine blades.
 13. A gas/liquid separator according to claim12 wherein the compressor means discharges separated gas at a pressureat least as great as the pressure of the gas/liquid mixture at theentrance to the turbine blades.
 14. A gas/liquid separator according toclaim 12 including a first chamber inside the rotor below the turbineblades for receiving separated gas; and a second chamber above therotor; and in which the compressor means rotate with the rotor todischarge separated gas upwardly from the first chamber to a gaspressure in the second chamber higher than the gas pressure in the firstchamber.
 15. A gas/liquid separator according to claim 12 wherein theinside surface of the rotor is generally conical and diverges downwardlyto a free lip at the bottom of the rotor to permit separated liquid andsolids in the liquid to fall under gravity from the bottom of the lip.16. A gas/liquid separator according to claim 12 in which the compressormeans comprises a plurality of fan blades on the rotor spaced closer tothe rotor axis than the turbine blades.
 17. A gas/liquid separatorcomprising:a housing having an inlet; a free-running rotor mounted forrotation about a vertical axis in the housing, the rotor having adownwardly diverging conical inside surface and being open at its lowerend; a first chamber in the housing below the conical inside surface ofthe rotor; a second chamber in the housing above the rotor; meansconnected to the inlet for directing flow of a gas/liquid inlet mixtureinto an upper end of the rotor partially radially outwardly from therotor axis and partially tangentially for rotating the rotor; and aplurality of fan blades on the rotor spaced relatively closer to therotor axis than the inside surface and extending from the first chambertoward the second chamber for discharging gas upwardly from the firstchamber to a pressure in the second chamber higher than the pressure inthe first chamber.
 18. A gas/liquid separator according to claim 17including a free lip at the bottom of the rotor.
 19. A gas/liquidseparator comprising:a hollow free-running rotor in the general form ofan inverted bowl mounted for rotation about a vertical axis; a chamberbelow the rotor; inlet means for introducing a gas/liquid inlet mixturepartially radially outwardly into an upper portion of the hollow rotorwith a sufficient tangential component for rotating the rotor wherebygas and liquid are separated in the rotor; means for dischargingseparated liquid from a lower portion of the rotating rotor into thechamber; means for withdrawing separated liquid from the chamber; andmeans for withdrawing separated gas from below the rotor.
 20. Agas/liquid separator according to claim 19 including a second chamberabove the rotor, and fan means on the rotor for discharging separatedgas upwardly from below the rotor to the second chamber at a gaspressure higher than the gas pressure in the chamber below the rotor.21. A gas/liquid separator as recited in claim 19 further comprisingmeans on the rotor for withdrawing gas from the chamber including meansfor increasing gas pressure to a pressure greater than pressure in thechamber.
 22. A gas/liquid separator as recited in claim 19 wherein theinside surface of the hollow rotor diverges in a downward direction. 23.A gas/liquid separator comprising:a housing; a free-running hollow rotormounted for rotation about a vertical axis in the housing, the rotorhaving a downwardly facing open end; means for introducing a gas/liquidmixture into the rotor adjacent an upper end of the rotor partially in aradially outward direction and partially in a tangential direction forrotating the rotor and centrifugally separating gas and liquid; achamber below the rotor for receiving separated gas and liquid from theopen end of the rotor; and means for separately withdrawing gas andliquid from the chamber.
 24. A gas/liquid separator as recited in claim23 wherein the means for withdrawing gas comprises fan means on therotor for increasing pressure of gas withdrawn from the chamber.
 25. Agas/liquid separator as recited in claim 23 wherein the rotor comprisesa downwardly diverging inside peripheral wall extending at least betweenthe open end and the means for introducing gas/liquid mixture into therotor.
 26. A gas/liquid separator as recited in claim 25 having a freelip at the open lower end of the rotor over which liquid can flow fromthe peripheral wall and a rubber ring surrounding the lower end of therotor.
 27. A gas/liquid separator as recited in claim 23 wherein thehollow rotor includes a generally conical inside peripheral wall.
 28. Agas/liquid separator comprising:a housing; a free-running rotor mountedfor rotation about a vertical axis in the housing, the rotor having adownwardly extending inside surface including a free lip at the bottomof the inside surface; means for directing a gas/liquid mixture into anupper portion of the inside of the rotor for rotating the rotor so thatgas and liquid are separated in the rotor and liquid travels downwardlyalong the inside surface of the rotor over the free lip; a chamber belowthe rotor for receiving separated gas and liquid; and means forseparately withdrawing gas and liquid from the chamber.
 29. A gas/liquidseparator as recited in claim 28 wherein the inside surface of the rotordiverges downwardly.
 30. A gas/liquid separator as recited in claim 29wherein the inside surface comprises a generally conical portion.
 31. Agas/liquid separator as recited in claim 29 further comprising a rubberring on the housing surrounding the free lip.
 32. A gas/liquid separatoras recited in claim 28 wherein the means for withdrawing gas comprisesfan means on the rotor for increasing pressure of gas withdrawn from thechamber.
 33. A gas/liquid separator comprising:a housing; a free-runninghollow rotor mounted for rotation about a vertical axis in the housing,the rotor having a downwardly extending inside surface; means adjacentan upper end of the inside surface of the rotor for directing flow of agas/liquid inlet mixture partially in a radially outward direction andpartially in a tangential direction for rotating the rotor andcentrifugally separating gas and liquid in the rotor; a first chamber inthe housing below the inside surface of the rotor for receivingseparated gas and liquid from the rotor; a second chamber in the housingabove the rotor; and passage means through the rotor extending from thefirst chamber toward the second chamber including a plurality of fanblades for discharging gas upwardly from the first chamber to a pressurein the second chamber higher than the pressure in the first chamber. 34.A gas/liquid separator according to claim 33 including a free lip at thebottom of the rotor.
 35. A gas/liquid separator as recited in claim 33wherein the inside surface of the rotor diverges in a downwarddirection.
 36. A gas/liquid separator according to claim 33 wherein theinside surface of the rotor is generally conical and diverges downwardlyto a free lip at the bottom of the rotor to permit separated liquid andsolids in the liquid to fall under gravity from the bottom of the lip.